An inﬁnite number of narrow parallel ditches meters apart have been dug out across a very long straight road. Prove that no matter how narrow these ditches are, a pedestrian with a step of length 1 meter inevitably steps into a ditch. via Moscow mathematical olympiad
Monthly Archives for May, 2013
Suppose you have a deck of cards. You have $1. You bet an amount x1 that the card dealt will be black (or red). After you see the card, you get paid x1 if you win and you lose x1 if you lose. Now you bet x2 that the next card will be black (or red, you get to pick). You win x2 if you … Continue reading the story "Gambling with cards"
A completely black dog was strolling down Main street during a total blackout affecting the entire town. Not a single streetlight had been on for hours. As the dog crosses the center of the road a Buick Skylark with 2 broken headlights speeds towards it, but manages to swerve out of the way just in time. How could the driver see the dog to swerve … Continue reading the story "In the dark"
Write the smallest positive integer that returns 0 results on a Google search. You can use any programming language/api to find the answer. via Gajanana GK.
How would you cut a rectangular cake into two equal pieces when a rectangular piece has already been cut out of it? The cut piece can be of any size and orientation. You are only allowed to make one straight cut. via Google interview puzzles
This puzzle is from Gardner's book "My Best Mathematical and Logic Puzzlez". You are playing poker with a friend, except that all the cards are shown face up. Here's how the game works: You first pick 5 cards (you can see all cards, so you can pick a royal flush if you want). Then your friend picks 5 cards (he can choose the cards he wants) Then you … Continue reading the story "Draw poker"
You participate in the long jump event at olympics and break the world record. However, you don't win any prize for the event. Why? via cartalk.com
Arrange 10 marbles on a floor so that there are 5 lines of 4 marbles each. via Math factor
A clerk at a butcher shop stands five feet ten inches tall and wears size 13 sneakers. What does he weigh? via Forbes